1. Technical Field to which the Invention Belongs
The present invention relates to a shield connector structure, for example, for the terminal connection of a shield electric wire to a motor of an electric automobile as well as for the ground connection of a shield portion of the shield electric wire to a case of a device.
2. Related Art
FIGS. 12 to 14 show an example of general shield connector structures.
The shield connector structure is for connecting a metal case 87 (FIG. 7) of a motor as a device and a winding 73 of a shield electric wire 72 (FIG. 14) as well as for providing the waterproof property to the connecting portion.
The shield connector structure is for connecting a metal case 87 (FIG. 12) of a motor as a device with a winding 73 of a shield electric wire 72 (FIG. 14) as well as for providing the waterproof property to the connecting portion.
As shown in FIGS. 12 and 13, the housing 74 has a flange portion 80 integrally. The flange portion 80 has a bolt insertion hole 81 (FIG. 13) so as to be fixed to a counterpart metal case by fastening with a bolt (not illustrated). Accordingly, the ground connection of the housing 74 with the case 87 is achieved via the flange portion 80.
As shown in FIG. 14, a large diameter storage room 82 for inserting the seal member 77 in the upper half portion, and a small diameter storage room 83 for storing the metal shell 75 and the shield stopper 76 in the lower half portion are formed in the housing 74, respectively. The outer periphery surface of the seal member 77 is closely contacted with the inner periphery surface of the storage room 82, and the inner periphery surface of the seal member 77 is closely contacted with the outer periphery surface of an outside coat 84 of the shield electric wire 72. According to the seal member 77, entrance of water or dusts from the storage room 82 of the housing 74 into the case 87 (FIG. 12) is prevented.
The metal shell 75 has a lower side cylindrical large diameter portion 88 and an upper side cylindrical small diameter portion 89. The metal shell 75 is contacted with the inner periphery surface of the storage room 83 of the housing via a plurality of spring pieces 90 provided on the outside of the large diameter portion 88. The vertex portions of the spring pieces 90 are contacted with the outer periphery surface of the large diameter portion 88, and the upper and lower base portions of the spring pieces 90 are contacted with the inner periphery surface of the storage room 83. Further, the winding 73 of the shield electric wire 72 is connected with the small diameter portion 89 of the metal shell 75 as well as the small diameter portion 91 of the shield stopper 76 is positioned at the outside of the small diameter portion 89 so that the metal shell 75 is held without falling out. The winding 73 can also be provided between the metal shell 75 and the shield stopper 76.
An inside coat 85 of the shield electric wire 72 is inserted through the metal shell 75 so as to be projected to the outside from the lower side holder 79. The winding 73 is exposed to the outside of the outer periphery of the inside coat 85 by stripping the outside coat 84. The shield stopper 76 elongates above the metal shell 75, and the lower end face of the seal member 77 is contacted with the upper side large diameter portion 92 of the shield stopper 76.
The upper end face of the seal member 77 is forced by a stopping plate 93. A corrugate tube 94 for protection outside the shield electric wire 72 is stored partially above the seal member 77 in the upper side storage room 82. A nail portion 96 of the holder 78 is engaged with a groove portion 95 of the corrugate tube 94 so that the corrugate tube 94 is stopped. The holder 78 is engaged with a hole portion 98 of the housing 74 by engaged with an engaging arm 97.
The lower side holder 79 is engaged with the housing 74 by an engaging arm 99 (FIG. 12) in the peripheral direction. The holder 79 is contacted with the metal shell 75 and the spring pieces 90 so as to prevent fall out of the metal shell 75 and the spring pieces 90. A circumferential groove 100 is formed in the housing 74 above the holder 79. A seal ring 101 is mounted on the circumferential groove 100. As shown in FIG. 12, the seal ring 101 is closely contacted with the inner peripheral surface of a hole portion 102 of the case 87 so as to prevent entrance of water or dusts from the lower side of the flange portion 80 into the case 87.
A terminal 86 is connected with the tip of the shield electric wire 72 by clamping. The conductor portion is exposed by stripping the inside coat 85 (FIG. 14) of the shield electric wire 72. The terminal (LA terminal, that is, a round plate terminal for an automobile) 86 is connected with the conductor portion by clamping. The terminal 86 is connected with the terminal portion of the motor (not illustrated) with a bolt by fastening.
However, according to the general shield connector structure, many components such as the metal shell 75, the spring pieces 90 and the shield stopper 76 are required for connecting the winding (shield portion) 73 of the shield electric wire 72 with the housing 74 so that the structure becomes complicated and bulky. Besides, since an expensive elastic material is used for the spring pieces 90 as well as a member without deformation should be used for the cylindrical metal shell 75 to be contacted with the spring pieces 90 for a good contact with the spring pieces 90. A high processing accuracy is required for each component so as to soar the cost, and thus it is problematic. Moreover, since the components, such as the metal shell 75, the shield stopper 76 and the seal member 77 are arranged vertically, the structure becomes bulky in the height direction, and thus a problem arises in that the installation operation of the shield electric wire 72 in an automobile (the entire length of the shield electric wire 72 is relatively short, for example, about 300 mm) and the assembly operation the devices in the case 87 are difficult. Furthermore, since components with a complicated structure, such as the metal shell 75, the spring pieces 90 and the shield stopper 76 are used, a problem is involved in that the assembly operation is difficult and thus a long time is required for the assembly.
Moreover, as shown in FIG. 15A, in the case the housing is tilted 74 in inserting the shield connector 71 from the tip end holder 79 side into the hole portion 102 of the case 87, there is a risk of interference of the seal ring 101 above the holder 79 to the opening end 102a of the hole portion 102 or interposition between the holder 79 and the opening end 102a as shown in the circled enlarged view (see FIG. 15B) so that the seal ring 101 is flawed.
In contrast, FIG. 16 shows a general shield connector structure (device connection structure of a shield electric wire) disclosed in JP-A-5-251116.
In the structure, a conductive inside ring 106 is inserted along an inside coat 105 of a shield electric wire 104, a winding 107 of the shield electric wire 104 is contacted with the outer periphery surface of the inside ring 106, and a flange portion 108 of the inside ring 106 is contacted with a case 109 of the device. The winding 107 and an outside coat 110 are held by an outside ring 111 onto the inside ring 106 from the outside of the shield electric wire 104, with a flange portion 112 of the outside ring 111 fixed on the case 109 by a bolt 113. The shield electric wire 104 is held and fixed by the outside ring 111 and the inside ring 106. A terminal (LA terminal, not illustrated) is connected with the conductor portion (core wire) 114 of the shield electric wire 104 by pressing. The terminal is same as the terminal 86 shown in FIG. 12.
However, according to the above-mentioned structure, in the case when the terminal is connected and fixed with a device, such as a motor, the bonded surface of the terminal and the bonded surface of the device are displaced in the rotational direction (in the electric wire peripheral direction as shown in the arrow "a" in the figure), the shield electric wire 104 is twisted so that the terminal and the device cannot be connected well. In the case they are connected forcibly, a problem is involved in that a stress is applied on the shield electric wire 104 in the twisting direction so as to cause damage according to time passage. In contrast, in the case the flange portion 112 of the outside ring 111 is fixed with the case 109 after connecting the terminal with the device, a problem arises in that the hole positions for the bolts 113 in the flange portion 112 and the case 109 cannot be coincided, and thus the fixing operation cannot be executed appropriately.
In view of the above-mentioned problems in the related arts, an object of the invention is to provide a shield connector structure with a simple and compact structure at a low cost, capable of improving the installation operation in an automobile and the assembling property by reducing a length (height direction) in an axial direction, capable of certainly assembling even in the case the terminal and the device are displaced in the electric wire peripheral direction, and capable of preventing flowing of the seal member according to the tilt of the housing.